690 resultados para 2003-07-BS
Resumo:
The ecology of arctic lakes is strongly influenced by climate-generated variations in snow coverage and by the duration of the ice-free period, which, in turn, affect the physical and chemical conditions of the lakes (Wrona et al., 2005, http://www.acia.uaf.edu/PDFs/ACIA_Science_Chapters_Final/ACIA_Ch08_Final.pdf). Most arctic lakes are characterised by a long period (8-10 months) of ice-cover, cold water and low algal biomass. The water temperature and nutrient concentrations, and most probably the nutrient input from the catchments, are closely related to the duration of snow- and ice-cover in the lakes. In years when the ice-out is late, - that is, in late July, - phytoplankton photosynthesis is limited by the lack of light and nutrients. Less food is then available to the next link in the food chain, such as copepods and daphnids, with implication on their growth rates.
(Table 2) Comparison of water chemistry in 1997 vs. 2003 of lakes in Zackenbergdalen, East Greenland
Grain size composition of bottom sediments from the Barents Sea sampled from R/V Ivan Petrov in 2003